We have three possibilities - intergovernmentalism, federalism or a federation of nation-states. In the light of experience it would seem advisable to seek the third option as our next step even if the second has my full sympathy.
Joschka Fischer, the German Foreign Minister, has made another important contribution to the political debate on the future of Europe in an interview this week with the Financial Times. It represents a development of his position compared to his landmark speech one year ago to Humboldt University in Berlin, where he called for a federal core group within an enlarged EU.
It also differs significantly from the ideas put for the EU's future by Mr Fischer's coalition partner, the leader of the SPD, Mr Gerhard Schroder. Mr Fischer insists that at this stage of the debate these are personal and party positions, not German government ones. They are all the more welcome for that, providing a framework in which this highly political question can be discussed throughout Europe.
It is as well to take full account of these trends during the intensifying political debate here about the Treaty of Nice, in the run-up to the referendum on June 7th. The treaty explicitly opens up a constitutional discussion and negotiation in an appended Declaration in the Future of the Union.
Four main issues are mentioned in the Declaration, ahead of another intergovernmental conference to meet in 2004: the delimitation of powers or "competences" between the EU and its member-states; whether the Charter of Fundamental Rights agreed at Nice should be given binding legal status; simplification of the treaties, and the role of national parliaments within the EU political system. Mr Fischer's latest thoughts chime in with this agenda. He draws a clear distinction between federalism and a federation of nation-states. In doing so he acknowledges crucial differences between Germany and other EU member-states, especially France, "where the nation cannot be separated from the state" and the UK, where "people do not want to give up the lively tradition of parliament for the benefit of some purpose-built structure on the continent".
Full federalism on the German model is not achievable in his lifetime, he now concedes. This conclusion builds on remarks he made in Dublin three weeks ago. Europe's ancient and diverse cultures and languages have developed in the context of the nation-state. The primary vehicle of its peoples' identities, the nation-state's "ongoing existence will be indispensable", he said. "This is the major difference to the history of the US constitution which otherwise offers many historically interesting parallels to current developments in Europe. But in Europe no one wants to abolish the nation-state, no one wants to create a European `superstate'."
This will not convince opponents of the Nice Treaty who say it paves the way for a superstate dominated by the larger states in a two-tier Europe. There is often an inflexible dogmatism in such pronouncements, which takes from their serious political intent and means they simply do not engage with their adversaries. Mr Fischer's latest remarks display a more open-minded attitude to his critics and raise a number of questions that must be addressed in any serious debate about the future of a continental-scale EU of 27 to 35 member-states.
Thus, in deference to French, British (and Irish) views about national sovereignty he now believes it will be necessary to combine the Council of Ministers and the European Commission as an executive, in contrast to Mr Schroder's proposal that the council become a second chamber of the European Parliament similar to the German Bundesrat or upper house.
He sees this as far preferable to the emergence of an advance guard of member-states committed to deeper integration (arguably the French government's preference), which could alienate member-states left out of the core group. In Dublin, he said the whole point about the new rules on enhanced co-operation or flexibility introduced in the Amsterdan and Nice treaties is that they will prevent such a core group developing outside the treaty framework. If so, the crucial question is to evaluate how effective they are in regulating such an uneven development.
Mr Fischer says intergovernmentalsm is another undesirable outcome because it would entrench stagnation and negotiating difficulties.
It would therefore risk reversion to the balance of power systems from which the EEC/EU has successfully rescued its member-states over the last 50 years, rendering a post-Cold War Europe unstable and disadvantaging the smaller member-states which have benefited most from pooling sovereignty and internationalising the rule of law.
Mr Fischer believes it is possible to combine a European identity with primary national ones in the creation of a transnationalised political project based on competing ideas of socio-economic organisation. Such a vision of multiple identities is rejected by those who say it is impossible to internationalise democracy and who therefore defend national sovereignty.
Secondly, there is the future of redistributive transfers with in the enlarged EU system. A commentary in Le Monde this week referred to Mr Schroder's "selfish Germany". The SPD's draft plan proposes to renationalise the Common Agricultural Policy and parts of its regional and cohesion funds, with the clear intent of reducing Germany's net contribution to the EU.
That would be an historic shift in the Franco-German relationship. It would also make it much harder for the candidate states to catch up with their more developed future partners.